1. Field of the Invention
The invention relates to an image sensor and a method for manufacturing the same, and more particularly to an image sensor formed by way of injection molding.
2. Description of the Related Art
A general sensor is used for sensing signals, which may be optical or audio signals. The sensor of the invention is used for receiving image signals or optical signals. After receiving image signals, the image sensor converts the image signals into electrical signals, which are then transmitted to a printed circuit board via a substrate.
Referring to FIG. 1, a conventional method for packaging an image sensor includes the steps of:
providing a substrate 10 having an upper surface 11 formed with signal input terminals 18 and a lower surface 13 formed with signal output terminals 24;
providing a frame layer 12 on the substrate 10 to form a cavity 11 together with the substrate 10;
providing a photosensitive chip 14 on the substrate 10 and within the cavity 11, a plurality of bonding pads 20 being formed on the photosensitive chip 14;
providing a plurality of wires 16 for electrically connecting the bonding pads 20 of the photosensitive chip 14 to the signal input terminals 18 of the substrate 10, respectively; and
providing a transparent layer 22, which is coated with an adhesive layer 23, on the frame layer 12 for covering and encapsulating the photosensitive chip 14.
The image sensor manufactured according to the above-mentioned method has the following drawbacks.
1. The image sensor has to be individually manufactured and cannot be manufactured in mass production, so the cost thereof cannot be decreased.
2. During the packaging processes, a substrate 10 has to be provided for each package body, and then a frame layer 12 has to be adhered to the substrate 10. Therefore, the manufacturing processes are inconvenient and the material cost may be increased. In addition, the overflowed adhesive may influence the wire bonding process.
An object of the invention is to provide an injection molded image sensor and a method for manufacturing the same, in which the mass production may be achieved by way of injection molding and the manufacturing cost may be effectively decreased.
Another object of the invention is to provide an injection molded image sensor and a method for manufacturing the same, in which a frame layer of the image sensor is formed by way of injection molding so that the overflowed adhesive or glue cannot influence the wire bonding process.
Still another object of the invention is to provide an injection molded image sensor and a method for manufacturing the same, in which metal sheets serve as a substrate and traces thereon so that the manufacturing cost may be effectively decreased.
To achieve the above-mentioned objects, the invention provides an injection molded image sensor for being electrically connected to a printed circuit board. The image sensor includes a plurality of metal sheets arranged in a matrix, an injection molded structure, a photosensitive chip, a plurality of bonding pads, a plurality of wires, and a transparent layer. Each metal sheet has a first board, a second board and a third board to form a -shaped structure. The injection molded structure encapsulates the metal sheets by way of injection molding and has a first molded body and a second molded body. The injection molded structure has a U-shaped structure and is formed with a cavity. The first boards of the metal sheets are exposed from a top surface of the first molded body to form signal input terminals, the second boards are exposed from a bottom surface of the first molded body to form signal output terminals, which are to be bonded to the printed circuit board, and the third boards are exposed from a side surface of the first molded body. The photosensitive chip is mounted within the cavity of the injection molded structure. The bonding pads are formed on the photosensitive chip. The wires electrically connect the bonding pads to the signal input terminals. The transparent layer covers over the first molded body to encapsulate the photosensitive chip.
To achieve the above-mentioned objects, the invention also provides a method for manufacturing an injection molded image sensor. The method includes the steps of:
providing a plurality of metal sheets arranged in a matrix, each of the metal sheets having a first board, a second board and a third board to form a -shaped structure;
performing a first injection molding process to seal the metal sheets and form a first molded body, wherein the first boards are exposed from a top surface of the first molded body to form signal input terminals, the second boards are exposed from a bottom surface of the first molded body to form signal output terminals, and the third boards are exposed from a side surface of the first molded body;
providing a connection board;
placing four first molded bodies around the connection board to form a U-shaped structure;
performing a second injection molding process to mold the first molded bodies and the connection board into a second molded body so that the second molded body is combined with the first molded bodies and is formed with a cavity;
placing a photosensitive chip, on which a plurality of bonding pads is formed, within the cavity;
providing a plurality of wires for electrically connecting the bonding pads to the signal input terminals; and
placing a transparent layer over the first molded bodies to encapsulate the photosensitive chip.